The popularity and convenience of the electric hand drill has made it a power source for many power tools. A myriad of tools have been fitted onto a rod and thereby become attachable to the chuck of the hand drill. For example, circular saws, hole saws, gears, pumps, screwdrivers, and the like are available today powered by the hand drill motor. Rechargeable batteries have now been made that are powerful enough to drive the drill motor and thereby free the drill from the necessity of being connected to an electric power source. The desire to use power tools rather than hand tools has led to inventions for rapid conversion of bits so as to save the time of unlocking one bit from the drill chuck, removing that bit, inserting a second bit, and locking it for use. Now it is popular to employ an adapter which is locked into the chuck by tightening the chuck key and bits are attached or removed in the same manner that a wrench socket is attached and removed from the wrench handle. These types of adapters are not acceptable for quality woodworking because the drill bits are not held tightly by the adapters, and thereby produce inaccurately drilled holes. The loose connection between bit and adapter is acceptable for screw-driving but not for drilling.
The patent prior art discloses some devices for quickly converting from an accurate power drill to a power screwdriver. See, for example, U.S. Pat. Nos. 4,092,753; 4,320,544; 4,363,250; and 4,796,319. All of these except the last one are complicated devices. The last one is much simpler, but it requires a special hexagonal drill holder.
It is an object of the present invention to provide a novel drill adapter. It is another object of this invention to provide a novel tool to convert a drill to a power screwdriver by a simple snap-on adapter. Still other objects will become apparent from the more detailed description which follows.